The present invention relates to a device for accessing fluid distribution pipelines, and particularly to a sealable coupling to affect such access.
Modern utilities have broadly adopted the use of inner pipeline liners to refurbish and rehabilitate low and medium pressure underground pipelines used for sewer, gas, and water distribution. The installation of such liners may be performed without pipeline excavation and can stop leaks and prevent future leakage. Rehabilitation of old pipelines to new pipeline specifications can save many thousands and perhaps millions of dollars in pipeline replacement costs. In addition, because the liner is installed without trenching and excavation, many environmental and municipal regulations may be circumvented which can save in regulatory permitting costs and in some circumstances litigation expense. Furthermore, in eliminating the necessity for excavation, surface obstructions or hazards otherwise associated with open trenches are eliminated.
Pipeline liners of this type are generally formed as an elongated collapsible elastomeric cylindrical tube impregnated with a polyester woven fabric. During installation, a continuous length of liner is selected, the diameter thereof conforming to the inside diameter of the pipeline and the length thereof corresponding to the length of pipeline to be fitted. The liner, in its collapsed state, is inserted into manholes or access junctions and drawn through the length of pipeline to be refurbished. Once the collapsed liner has been fully introduced into the pipeline, the liner is thereafter expanded to conform to the inner diameter of the pipeline. The outer surface of the liner is usually provided with an adhesive so that when the liner is expanded, the liner bonds to the inner pipeline surface. The adhesive is allowed to dry and the pipeline thereafter reintroduced into service.
Typically when it is subsequently desired to couple to such a lined pipeline, for instance to provide service to new residential communities, an access pit is excavated around a length of pipeline at a selected intermediate location along the length thereof. Thereafter, the pipeline may be taken out of service, evacuated of pressurized fluid, and a hole is bored or drilled into the pipeline and through the liner. On the outer surface of the pipeline, a sealing gasket is placed about the periphery of the bore hole and an appropriate saddle connector, or the like, having a fluid bore therethrough is fitted around the pipeline to complete the coupling. Although, conventional saddle connectors of this sort have proven effective for effectuating fluid access to distribution pipelines, they do not provide a means for sealing the internal liner relative to the pipeline.
It is imperative that the integrity of the adhesive bond between the liner and pipeline around the bored hole be maintained. Should the liner become separated from the pipeline at the bore hole, the integrity of the refurbished pipeline and effectiveness of the liner may be destroyed. Therefore, it is desirable that the point of penetration into the pipeline and around the coupling be effectively sealed to maintain or improve the integrity of the bond between the liner and the pipeline.
In similar fields of endeavor, others have developed devices for coupling or teeing into fluid reservoirs. A coupling device of this nature is disclosed in U.S. Pat. No. 567,115 to Atkinson et. al. In general, the coupling disclosed in the patent is for connecting to a water closet having a fluid ejectment hole in the sidewall thereof for receipt of a coupling stem or short section having an axial bore therethrough. One end of the stem includes threads on the external surface for connection to piping. The other end of the coupling stem has pivoted therefrom a plurality of longitudinally projecting fingers each having outwardly projecting hooks extending from the respective distal ends thereof. The fingers are pivoted inwardly during installation so that when the coupling stem is introduced into the water closet ejectment hole, the hooks pass therethrough. Once the stem is disposed within the ejectment hole, a wedge device having a fluid bore therein is inserted into the axial bore of the stem and advanced therethrough, the bottom edge of the wedge pivoting the ends of the fingers outwardly so that the hooks may engage the periphery of the bore hole. An annular gasket and bolt thereafter are placed over the stem and the bolt threadedly advanced over the stem until the gasket and reservoir wall are compressed between the hooks and the bolt, the gasket facilitating a fluid seal. Devices as this have proven effective in use however, the gasket seal arrangement such as this does not seal the annular volume between the stem and the bore hole.
Another coupling device is disclosed in U.S. Pat. No. 3,981,061 to Jackson et. al. The coupling device has a stem section, one end thereof having a pair of rigidly formed oppositely and outwardly projecting legs. A heel-and-toe manipulating action is required to insert the legs into a pipeline bore hole. The rigid legs engage the inner peripheral portion of the pipeline bore hole when a bolt or the like is tightened down upon outwardly projecting opposite end of the stem. Although this type of device allows for the flowing of a pliable sealant into the annulus between the stem and bore hole, the rigid configuration of the legs and heel-and-toe manipulation of the coupling may prove difficult when installing in a confined area.
Hence, those skilled in the art have recognized the need for a coupling device to access a fluid distribution pipeline having a liner disposed therein, and more particularly to a coupling device which allows for flowing of a sealant into the open volume between the coupling device and a bore hole formed in the pipeline and liner. It is also desirable for such a coupling device to have the ability for installation into pressurized pipelines. In addition, the coupling device should be easy to install, reliable in use, and inexpensive to manufacture. The present invention meets these needs and others.